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Upright Bass Fingerboard Reglue
Hey everyone, I had a question on regluing the fingerboard on an 3/4 scale upright bass. The surface of the neck where the neck/fingerboard meet is fairly clean and shouldn’t pose too much of a problem, however, the fingerboard itself has a fairly significant backbow of around 1/16″ or 3/32″. I’m wondering if you all had any suggestions on how to manage this. The customer would be pleased for the bass to be put back together and considers it something of a knock around instrument. I have two thoughts:
-Create a “sled” and route the underside of the fingerboard so that it’s roughly flat, then sand it flat and glue it to the neck. Since the fingerboard is quite a thick piece of ebony, I think this is doable although perhaps not ideal.
-Scrape the glue from the underside of the fingerboard and apply heat/steam from an iron, and then clamp it a slight upbow and leave it to set. Or maybe use heat blankets or something of this sort. I’m less enthused by this since I’ve never had great luck with this method. Also, considering the thickness of the board, I’m not sure how viable this would be.
Any advice would be appreciated, thanks!
-David
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11 Replies
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Hey there! What I would do, before going heavy on it, would be trying to put it back to its ‘straightness’. Something like the pic attached (randomly found on Google). I would not add too much water/moisture to it, but a little steam, or heat, could help.
Even if it doesn’t came totally straight again once freed from the jig, you could then just file it a little (since it seem quite thick) with a plane.If that won’t work you can always change approach and, eventually, go heavy if needed.
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Hey Alex, yeah this was one of the options I was thinking of. As far as applying heat and/or steam, when in the process would you recommend doing it? Would you do it and then clamp, or do it after it’s already clamped?
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A mix of both is the best option (in my opinion). Probably heat is the first solution I would try. Heat a bit and clamp it, then repeat.
But, I have a question: does it bent when you have removed it, or it was already bent before? (Just to know)
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I’ll give that method a shot and see what progress I make with it. My understanding is that my customer bought the bass several months ago and the fretboard was off back then. I don’t know exactly how long its been off but quite awhile I’d imagine.
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Oh ok, just to guess if it would straighten back again naturally if it was removed not long ago.
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+1
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I’ve been able to bend full-thickness bass fingerboards. It’s occasionally done to correct movement of the board beyond the foot of the neck, sometimes scooped in that area… sometimes not.
I would, personally, hesitate use the suspended heating setup, while it’s a gentle heat, I but would clamp it flat to a neck heater or whatever flat hot thing you use, a bit of moisture certainly doesn’t hurt. Clamp it flat, let it get hot then turn off the heater but leave it clamped overnight. I think a towel or something over the top to slow the cooling helps too.
Beyond that, I would chalk fit the fingerboard to the neck (with the neck as straight as possible and fixed in that position) and plane the board to adjust the camber as needed. You don’t want to let the board get too thin, ideally 10mm+ on the sides.
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What would you recommend as far as a commercial neck heater is concerned? A local luthier friend of mine uses this Aria one. I tried to find something similar online but never could.
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Sorry. Very late to this. If your still working on it, maybe this will help? I was able to straighten a much shorter version of your problem. I used heat lamps and a reflector to get a neck (it had a back bow of 3/32) straight. I was thinking heat lamps because your fingerboard is so much longer than most. You can string them along the length of the fingerboard and the reflector heats the whole thing up, not just from the top (I saw a vid of Scott D from Harpeth Guitar Restoration use the reflector successfully). I clamped it as most do with 3/32 of up bow hoping it would spring back to flat. I got it very hot (300 degrees and I had tried less heat and let it cool but didn’t work and nothing left to lose) and you don’t have to worry about glue problems because your working with a piece of wood with nothing attached. But here’s what I think helped it to work. I used a damp sponge and wet the surface back and forth along the length a few times. Steam came off the neck. I then let it cool for a few days and it worked. It was flat when I released the clamps.
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Nice !
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Upright bass fingerboards often have a LOT of relief so you can’t really clamp it flat. I’d be more inclined to put a beam on the back of the neck which in general is flat to keep things straight. Or something. I don’t know. But don’t put something super flat against the fingerboard.
You def want to scrape all the old glue off both surfaces.
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